How do you check whether a number is special number or not by Java?

Answer 1

It depends what you regard as being "special". Once you define the criteria for "special" you can formulate an algorithm that determines whether or not a given number meets that criteria. For instance, if you regard prime numbers as being special, you need a predicate to test whether a given number is zero, prime or composite. If prime then it is indeed special, otherwise it isn't. A predicate is a function that returns true or false depending on its input(s).

As a simple example, if we regard even numbers as being special, then we need to test if the number has the prime factor 2. If so, it is special, otherwise it is not. We can test this by dividing the number by 2 and testing the remainder. If the remainder is zero, the number is even and is therefore special. We use the modulo operator (%) to determine the remainder after integer division:

bool is_even (int n) { return (n % 2) == 0; }

Answer 2

First, decide WHAT SORT OF properties you want to check for, to label a number as "special".Then, write a method to check for each of those properties; for example:

* Is the number a square number, or some other power?

* Is the number a Prime number?

* Is the number a perfect number?

etc.